Solar Wire Size..??? Fuses on panels...??

It sounds like you already have a supply of good 10 AWG at hand. I would double that from the panels and install a circuit breaker like this Manual reset breaker before the controller. Since this breaker accepts large lugs, you can join the two panel 10 ga runs at the breaker and lead out a 4 awg wire to the controller. This will afford circuit protection but also an easy disconnect.

Good luck with your solar installation.